Promotion of microvasculature formation in alginate composite hydrogels by an immobilized peptide GYIGSRG

Modification of Alginates to Modulate Their Physic-Chemical Properties and Obtain Biomaterials with Different Functional Properties

Modified alginates have a wide range of applications, including in the manufacture of dressings and scaffolds used for regenerative medicine, in systems for selective drug delivery, and as hydrogel materials. This literature review discusses the methods used to modify alginates and obtain materials with new or improved functional properties. It discusses the diverse biological and functional activity of alginates. It presents methods of modification that utilize both natural and synthetic peptides, and describes their influence on the biological properties of the alginates. The success of functionalization depends on the reaction conditions being sufficient to guarantee the desired transformations and provide modified alginates with new desirable properties, but mild enough to prevent degradation of the alginates. This review is a literature description of efficient methods of alginate functionalization using biologically active ligands. Particular attention was paid to methods of alginate functionalization with peptides, because the combination of the properties of alginates and peptides leads to the obtaining of conjugates with properties resulting from both components as well as a completely new, different functionality.

A functional chitosan-based hydrogel as a wound dressing and drug delivery system in the treatment of wound healing

Functional active wound dressings are expected to provide a moist wound environment, offer protection from secondary infections, remove wound exudate and accelerate tissue regeneration, as well as to improve the efficiency of wound healing. Chitosan-based hydrogels are considered as ideal materials for enhancing wound healing owing to their biodegradable, biocompatible, non-toxic, antimicrobial, biologically adhesive, biological activity and hemostatic effects. Chitosan-based hydrogels have been demonstrated to promote wound healing at different wound healing stages, and also can alleviate the factors against wound healing (such as excessive inflammatory and chronic wound infection). The unique biological properties of a chitosan-based hydrogel enable it to serve as both a wound dressing and as a drug delivery system (DDS) to deliver antibacterial agents, growth factors, stem cells and so on, which could further accelerate wound healing. For various kinds of wounds, chitosan-based hydrogels are able to promote the effectiveness of wound healing by modifying or combining with other polymers, and carrying different types of active substances. In this review, we will take a close look at the application of chitosan-based hydrogels in wound dressings and DDS to enhance wound healing.

Peptide REDV-modified polysaccharide hydrogel with endothelial cell selectivity for the promotion of angiogenesis

Rapid and controlled vascularization of engineered tissues remains one of the key limitations in thick tissue engineering. Although many studies have focused on improving the rapid vascularization through the immobilization of bioactive molecules, the competition in growth between endothelial cells (ECs) and other cell types is to some extent neglected. In this study, we developed a peptide GREDV-modified scaffold for selective adhesion of human umbilical vein endothelial cells (HUVECs) through the specific recognition of the REDV peptide and integrin α4 β1 . In vitro studies showed that GREDV-conjugated alginate (ALG-GREDV) improved HUVEC adhesion, migration and proliferation when compared with a non-modified group. Furthermore, ALG-GREDV exhibited a superior capability for promoting the proliferation and selective adhesion of HUVEC over that of other peptide (RGD and YIGSR) modified groups (ALG-Pep). In vivo angiogenic assays demonstrated that the ALG-GREDV scaffold induced an angiogenic potential by stimulating new vessel formation and showed the highest blood vessel density among all samples after 21 days of implanting (83.7 vessels/mm(2) ). More importantly, the blood vessel density in cambium fibrous tissue of ALG-GREDV was about 1.5 times greater than other ALG-Pep groups, indicating facilitation of ALG-GREDV on selective angiogenesis in vivo. These results demonstrated that REDV-conjugated alginate could be a useful scaffold for stimulating and inducing angiogenesis in tissue-engineered applications.